Mounting circuit breaker operating mechanisms



Oct. 18, 1966 E. c. GOODWIN 3,280,289

MOUNTING CIRCUIT BREAKER OPERATING MECHANISMS Original Filed March 25, 1964 2 Sheets-Sheet 1 elude 14x0) 8,01 1 1% m E jppA l MM Oct. 18, 1966 E. c. GOODWIN 3,280,289

MOUNTING CIRCUIT BREAKER OPERATING MECHANISMS 2 Sheets-Sheet 2 Original Filed March 25, 1964 United States Iatent C) 3 280,289 MOUNTING CIRCUIT BREAKER OPERATING MECHANISMS Edwin C. Goodwin, Canton, Mass., assignor to Allis- Chalmers Manufacturing Company, Milwaukee, Wis. Continuation of application Ser. No. 354,633, Mar. 25, 1964. This application Nov. 12, 1965, Ser. No. 514,738 2 Claims. (Cl. 200-153) This application is a continuation of my copending application for Mounting Circuit Breaker Operating Mechanmism, Edwin C. Goodwin, Serial No. 354,633, filed March 25, 1964, and reference is made thereto for purposes of obtaining the benefit of the filing date thereof.

This invention relates generally to electrical circuit breakers and more particularly to improvements in the mounting of operating mechanisms which open and close the circuit breaker contacts.

In some installations a circuit breaker having an enclosure or tank with movable contacts therein is rigidly mounted on supports. An operating mechanism for opening and closing the circuit breaker contacts is enclosed within a protective housing or cabinet which is also mounted on the same supports adjacent the circuit breaker. The operating mechanism opens and closes the circuit breaker contacts by means of a movable shaft, usually rotatable, which extends from the cabinet into the tank. Since the operating mechanism is relatively heavy and exerts powerful forces during its operation, it has heretofore been necessary to make the supports adjacent the operating mechanism of a strength greater than that required to support the breaker tank structure and to attach to these supports heavy bracing means in order to adequately mount and support the operating mechanism attached thereto by numerous bolts passing through the wall of the cabinet and into said supports and braces. In other applications it has been necessary to provide a very sturdy cabinet in order to provide the rigidity necessary to withstand the powerful forces exerted by the operating mechanism. The foregoing types of construction are une-conomical in that they require numerous manufacturing operations and the use of relatively costly materials in the fabrication of the operating mechanism supporting means.

In accordance with the present invention, the movable shaft is entirely supported by bearing means on the circuit breaker and the operating mechanism within the cabinet is supported on the shaft which it rotates instead of directly on the supports, and those forces which in prior art act to separate the breaker actuating lever from the operating mechanism are now confined within the frame of the operating mechanism. To prevent rotation or other reactive movement of the operating mechanism during its operation, the operating mechanism is secured, for example, at one point to some portion of the cabinet. As a result, the cabinet and its bracing means can be constructed of lighter, more economical materials and numerous manufacturing operations can be eliminated. -In addition, the operating mechanism can be more easily mounted or removed from the cabinet for servicing.

It is, therefore, an object of this invention to provide improved means for mounting the operating mechanisms of circuit breakers.

Another object is to provide an arrangement wherein the operating mechanism is supported on the movable contact operating shaft of the circuit breaker instead of directly on the supports or on a wall of the cabinet which houses the operating mechanism.

Another object is to provide an arrangement comprising -a circuit breaker and cabinet for the operating mechanism thereof wherein the cabinet and its bracing means are more economically constructed than has heretofore been possible.

Another object is to provide improved means for mounting circuit breaker operating mechanisms within a cabinet so that the operating mechanism can be more easily installed and removed.

Another object is to provide increased accessibility for inspection and adjustment of those components which are associated with and required for the control of the operating mechanism.

Other objects and advantages will become apparent from the following description in conjunction with the attached drawings, in which:

FIG. 1 is a front view of an installation comprising a circuit breaker and a control cabinet with a portion of the cabinet cut away to show an operating mechanism for controlling the circuit breaker contacts;

FIG. 2 is a side view of the installation shown in FIG. 1 with a portion of the cabinet cut away to show the operating mechanism;

FIG. 3 is an enlarged top view of a portion of the installation shown in FIGS. 1 and 2 with portions of the circuit breaker dome and cabinet cut away to show interior details thereof;

FIG. 4 is a section along lines IVIV of FIG. 3 also showing the interior of the circuit breaker; and

FIG. 5 is a section along lines VV of FIG. 4.

Referring to FIGS. 1, 2 and 3, there is shown an installation comprising an oil type circuit breaker 10 which is rigidly supported above ground by a plurality of angle irons 11, four being shown, which are attached thereto. For stability, the angle irons 11 are, for example, braced at their feet by angle irons 12 and tie bars 14.

As FIGS. 1 through 5 show, circuit breaker 10 comprises a cover or dome 15 and a tank 116. Dome 15 supports three pairs of insulating bushings 18, one pair for each phase of a three phase electrical power circuit. Referring to FIG. 5, it is to be understood that each bushing 18 is equipped at its end inside tank 16 with an arc interrupting device 19 which houses a stationary contact 20 which is electrically connected to a conductor 21 within the respective bushing.

Means are provided to electrically connect and disconnect the stationary contacts 20 in each pair of interrupting devices comprising each phase. Thus, as FIG. 3 shows, a rotatable hexagonal shaft 22 extends into circuit breaker 10 through a short pipe or conduit 23 which is rigidly secured in dome 15 of the circuit breaker. Shaft 22 is supported for rotational movement by a bearing 24 located in conduit 23 on dome 15 and by another bearing 25 provided on a bracket 26 which is rigidly secured inside dome 15, as by the bolts 28, or other fastening means. Shaft 22 is provided with a pair of cranks 29 which are rigidly secured at one end to the shaft and at their other end to a horizontal bar 30 which is recip rocally movable in a vertical direction in guide slots 31 provided in the depending portions of bracket 26. Bar 30 is secured to the upper ends of three reciprocally movable insulating rods '32. The lower end of each insulating rod 32 is rigidly secured to an electrically con- 3 ductive cross arm 34 which has a pair of bayonet type contacts 35 thereon, one contact being disposed at each end of the cross arm. Each contact 35 is adapted for reciprocal movement into and out of engagement with the stationary contact 20 mounted in the arc extinguishing device 19 associated therewith.

Means, such as a stored energy contact operating mechanism 36, is provided to rotate shaft 22 to effect operation of the circuit breaker contacts. Operating mechanism 36 is enclosed or housed within a cabinet or housing 38 which is preferably fabricated of sheet metal.

Cabinet 38 is supported near its upper end by having its rear wall 39 attached to conduit 23 and another conduit 40, both of which are rigidly secured to dome 15 of circuit breaker 10. Cabinet 38 is further supported near its lower end by a strap 41 which is secured to its rear wall 39 and to two of the angle irons 11, as by bolting or welding.

Operating mechanism 36 is, for example, a modular unit adapted for use with several types of circuit breakers. Operating mechanism 36 comprises a back plate 42 and a front plate 43 which are secured to each other in spaced apart relationship by means of braces 44 and support suitable operating linkage therebetween, including a lever 48 which is pivotabie about a point on the axis of shaft 22. Lever 48 is connected by linkage 49 to a contact opening spring 50 and is also connected by linkage 51 to a contact closing spring 52. Operating mechanism 36 further comprises means such as an electric motor 54 and a gear unit 55 for effecting charging of closing spring 52. As will be understood, discharge of contact ciosing spring 52 effects movement of linkage '1 and pivoting of lever 48 in a counterclockwise direction '(with respect to FIG. 1) and also effects charging of contact opening spring 50. Discharge of contact spring 50 in response to a fault condition in the electric circuit being protected by circuit breaker effects movement of linkage 49 and pivoting of lever 48 in a clockwise direction (with respect to FIG. 1). Discharge of contact closing spring 52 effects energization of electric motor 54 and consequent recharging of contact closing spring 52 to place it in readiness for the next cycle of operation.

Means are provided to connect operating mechanism 36 to shaft 22 so that the operating mechanism is mechanically supported on the shaft and is also able to effect rotation of the shaft in opposite directions for contact opening and closing purposes. Thus, shaft 22 extends through the plates 42 and 43 of operating mechanism 36 and supports the latter by means of bearings 45 and 46 which are mounted on the plates 42 and 43, respectively. Lever 48 is located between the bearings 45 and 46 and is rigidly clamped to shaft 22 to eifectrotation thereof in the appropriate direction.

As will be understood, the springs 50 and 52 are quite powerful and when discharged tend to cause reactive rotational movement of operating mechanism 36 in a direction opposite to the direction in which shaft 22 is rotated. Accordingly, means are provided to anchor operating mechanism 36 against such reactive movement. As FIG. 2 shows, a bracket member 5 6 is secured to opcrating mechanism 36, preferably at a point as remote as possible from the axis of shaft 22, by means of a bolt 57 and is also secured to rear wall 39 of cabinet 38 by means of one or more bolts 58. The bolts 58 are not required to serve in any way as mechanical support for operating mechanism 36 on cabinet 39 but only serve to prevent rotation of the operating mechanism. It is to be understood that the entire weight of operating mechanism 36 is supported by shaft 22 which is in turn supported by dome of circuit breaker 10. Thus, cabinet 38 need not be fabricated of heavy gauge sheet metal or The apparatus hereinbefore described operates as follows: Assume first that the contacts of circuit breaker 10 are closed, that contact opening spring 50 is fully charged and that lever 48 is in the position shown in FIG. 1. As a result of manual tripping or automatic tripping in the event of a fault condition, opening spring 50 discharges and linkage 49 causes lever 48, shaft 22, and cranks 29 to move clockwise. Such movement of cranks 29 lowers bar 30, the insulating rods 32, and cross arms 34 and causes each bayonet contact 35 located thereon to disengage from the stationary contact 20 in its respective arc extinguishing device 19.

Contact closing spring 52 which has been charged by electric motor 54 through gear unit 55 prior to the opening operation now discharges due to manual tripping or due to tripping from an electrical signal. This causes linkage 51 to move lever 48, shaft 22 and cranks 29 counterclockwise with respect to FIG. 1. Such movement of cranks 29 raises bar 30, the insulating rods 32 and the cross arms 34 and causes each bayonet contact 35 to make contact with the stationary contact 20 in its respective arc extinguishing device 19. Thus, the circuit breaker returns to the closed contact position. All of the FIGS. 1 through 5 are intended to illustrate this closed condition. It is to be understood that the discharge of closing spring 52 also effects the charging of opening spring 50. Furthermore, immediately upon discharge of closing spring 52, electric motor 54 is energized and through gear unit 55 efiects the recharging of contact closing spring 52 to put it in readiness to reclose the circuit breaker contacts should they again trip open.

Although but one embodiment is illustrated and described it will be apparent to those skilled in the art that various changes and modifications can be made herein without departing from the spirit of the invention or the scope of the appended claims.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. In combination, a supporting structure, an electric circuit breaker mounted on said supporting structure, a movable contact in said circuit breaker, a movable shaft supported on said circuit breaker for moving said movable contact, an operating mechanism housing rigidly mounted on said circuit breaker and having an opening for accommodating said shaft which extends into said housing whereby said housing is unsupported by said operating springs for moving said shaft when discharged,

said springs when discharged exerting reactive forces tending to cause reactive movement of said operating mechanism with respect to said shaft and said housing, and means for connecting said operating mechanism to said housing for preventing reactive movement of said operating mechanism as the latter moves said shaft, said means being connected to only a single point on one of said plates of said operating mechanism.

2. In combination, a supporting structure, an electric circuit breaker mounted on said supporting structure, a movable contact in said circuit breaker, a rotatable shaft supported on said circuit breaker for moving said movable contact, said shaft extending horizontally from said circuit breaker, an operating mechanism housing rigidly mounted on said circuit breaker and having a sheet metal wall lying in a plane which is transverse to the axis of said shaft, said wall having an opening for accommodating said shaft which extends into said housing whereby said housing is unsupported by said shaft, an operating mechanism in the form of a modular unit disposed within said housing and supported entirely on said movable shaft, said operating mechanism comprising spaced apart plates which support stored energy operating springs for 5 rotating said shaft when discharged, said plates lying in planes which are parallel to the said plane in which said wall lies, said springs when discharged exerting reactive forces tending to cause reactive rotation of said operating mechanism around said shaft, and means for connecting said operating mechanism to said housing for preventing reactive rotation of said operating mechanism as the latter rotates said shaft, said means being connected between only a single point on one of said plates of said operating mechanism and said wall whereby forces are transmitted to said wall in a direction lying Within the plane in which said Wall lies.

No references cited.

ROBERT K. SCHAEFER, Primary Examiner. 

1. IN COMBINATION, A SUPPORTING STRUCTURE, AN ELECTRIC CIRCUIT BREAKER MOUNTED ON SAID SUPPORTING STRUCTURE, A MOVABLE CONTACT IN SAID CIRCUIT BREAKER, A MOVABLE SHAFT SUPPORTED ON SAID CIRCUIT BREAKER FOR MOVING SAID MOVABLE CONTACT, AN OPERATING MECHANISM HOUSING AN OPENING MOUNTED ON SAID CIRCUIT BREAKER AND HAVING AN OPENING FOR ACCOMMODATING SAID SHAFT WHICH EXTENDS INTO SAID HOUSING WHEREBY SAID HOUSING IS UNSUPPORTED BY SAID SHAFTS, AN OPERATING MECHANISM IN THE FORM OF A MODULAR UNIT DISPOSED WITHIN SAID HOUSING AND SUPPORTED ENTIRELY ON SAID MOVABLE SHAFT, SAID OPERATING MECHANISM COMPRISING SPRINGS FOR MOVING SAID SHAFT WHEN DISCHARGED, OPERATING SPRINGS FOR MOVING SAID SHAFT WHEN DISCHARGED, SAID SPRINGS WHEN DISCHARGED EXERTING REACTIVE FORCES TENDING TO CAUSE REACTIVE MOVEMENT OF SAID OPERATING MECHANISM WITH RESPECT TO SAID SHAFT AND SAID HOUSING, AND MEANS FOR CONNECTING SAID OPERATING MECHANISM TO SAID HOUSING FOR PREVENTING REACTIVE MOVEMENT OF SAID OPERATING MECHANISM AS THE LATTER MOVES SAID SHAFT, SAID MEANS BEING CONNECTED TO ONLY A SINGLE POINT ON ONE OF SAID PLATES OF SAID OPERATING MECHANISM. 